Glass is a good packaging material for pharmaceutical products like tablets, capsules, syrup, and suspension in glass bottles and sterile products in the form of ampules or vials.
Glass was discovered in 3000 BC, and from that time it has been widely used in the packing of pharmaceutical and food products. Glass is preferred pharmaceutical packaging material because of its high level of barrier property for moisture and gases.
Manufacturing & Composition Of Glass
- The main component of glass is silicon dioxide or sand or silica and it also contains soda ash, limestone and cullet.
- Cullet Is broken glass that is used in the manufacturing process and mixed with batch and acts as a fusion agent.
- Glass is prepared by heating the sand or silicon dioxide,limestone (as calcium carbonate),soda ash (as Sodium carbonate) and cullet.
- On heating at high temperature a molten mass is produced which is then cooled and converted into glass.
- Others ingredients used are are as follow
- Selenium or Cobalt Oxide
- Lead Oxide
- Alumina
- Boron
- Arsenic Trioxide and Sodium Sulphate
- Colourants
Selenium or Cobalt Oxide
Selenium or cobalt oxide give better clarity to the glass.
Lead Oxide
Lead Oxide gives clarity to glass but it also makes the glass soft.
Alumina
It Increases glass hardness,gives clarity and durability.
Boron
Boron results in low thermal expansion of glass.It also gives high heat resistance to the glass.
Arsenic Trioxide and Sodium Sulphate
These are used to reduce blistering of glass.
Colourants.
Different colors and materials are used to give a specific color to glass for different purposes e.g amber color glass is used for pharmaceutical packaging of those products which are degraded by the light.
Amber Color Glass
For amber color it contains carbon and sulphur or iron and manganese.
Blue glass
It contains Cobalt with copper
Green Glass
It contains Chromium with iron and Manganese
Advantages of Glass
Following are some main advantages of glass containers to used as pharmaceutical packaging material
Compatible
Glass is compatible for most of the pharmaceutical products so it can easily be used for packaging of pharmaceutical products.
Impermeable
Glass provides strong barriers for gases and moisture penetration so keep inside products stable.
Heat Stable
Stable for holding hot products.
Visibility
Clear Glass containers allow visual inspection because the product is visible.
Light Protection
Amber color glass is used to protect the light sensitive products.
Sterilization
Product packed in glass packaging material can easily be sterilized.
FDA Approved
Glass as a packaging material is approved by the FDA and it does not deteriorate in storage with passage of time.
Dis-Advantages Of Glass Packaging
Following are some disadvantages of glass packaging,
Cost
Cost of glass packaging material is high.
Cost of transportation to market after packaging is also high.
Weight
Glass is Heavy weight so difficult for handling.
Brittle
Glass is Brittle so chances of breakage are high during transportation.
Product Loss
Product loss occurs in case of damage to glass packaging material.
Ion Leaching
Leaching of ions may take place.
Types Of Pharmaceutical Glass
Following are types of glass
- Type I Glass
- Type II Glass
- Type III Glass
- Type IV Glass/Type NP
Type I Glass
- Type I glass contains a high level of boric oxide so it is also known as borosilicate glass.
- The Type I glass is Highest grade Of Pharmaceutical glass.
- Type I glass consists of
- Boric Oxide
- Aluminium Oxide
- Alkaline earth oxide
- The type I glass is the most inert type of pharma glass having highest hydrolytic resistance and the lowest leaching effect.
- It is highly resistant to heat.
- Its Cost of manufacturing is very high.
- It can easily be sterilized.
Uses of Type I Glass
- Type I glass is used for packaging of
- Parenteral Products.
- Type I glass is used for packaging of
- non- parenteral Products.
Type II Glass
- Type II Glass glass is made of soda lime alkali glass.
- Type II Glass contains Sodium Oxide and Calcium Oxide.
- Type II Glass has average hydrolytic resistance.
- Hydrolytic resistance of Type II Glass is increased by treating the inner surface of type II glass containers with sulphur dioxide.
- Due to sulphur dioxide treatment the oxides on the surface react with sulphur dioxide e.g sodium oxide on the surface is converted into sodium sulphate and sodium sulphate can easily be removed from the surface by washing the glass containers.
- This treatment with sulphur dioxide reduces the chances of ions leaching and increases the hydrolytic resistance of Type II glass.
- Type II glass is also known as treated soda lime glass or De-alkalized glass.
Uses of Type II Glass
Type II glass are used for following
- Acidic Aqueous Preparations
- Neutral Aqueous Preparations
- Parenteral Preparations
- Non parenteral Preparations
Note:
Type II glass are not suitable for packaging of basic preparations.
Type III Glass
- Type III glass is simple soda lime silica glass.
- Type III Glass has moderate hydrolytic activity.
- When type III is treated with sulphur dioxide it becomes type II glass.
Uses of Type III Glass
- Type III Glass is used for non parenteral products.
- Type III glass is not suitable for aqueous parenteral products.
- Type III glass can be used for non aqueous parenteral products like sterile powders.
Type IV Glass Containers/Type NP
- Type IV glass is also known as NP Non Parenteral general purpose soda lime glass.
- Type IV glass has low hydrolytic resistance.
- It is not suitable for autoclave.
Uses of Type IV Glass
- It is not used for Sterile products.
- It is used for topical products.
- It is used for Oral Dosage forms.
Test For Glass Containers
Following test are used for glass containers
- Crushed Glass Test
- Whole Container Test
- Water Attack Test
- Chemical Resistance Test
References:
- Bentley’s textbook of pharmaceutics
- Aulton’s Pharmaceutics
- The Theory & Practice of Industrial Pharmacy (Leon Lachman)